MIAMI—For nearly 10 years, Greg Allgood has been working on the problem of clean drinking water for one of the biggest corporations in America – Procter & Gamble, the maker of Tide detergent, Crest toothpaste and Pampers, the disposable diapers.
Procter & Gamble also makes a powder containing chlorine and iron sulfate that people [...]

NEW DELHI—Bhola Nishad spends his days on a dusty bluff overlooking the Yamuna River. Like so many Indians, Mr. Nishad regards the river as a holy place. It is also his place of business.
All along the river as it winds through New Delhi, the capital of India, devout Hindus stop to toss into the dark, [...]

MIAMI—This is the story of a tree and what it means to the water supply and to the global environment. It is an ancient story but it is also a story as modern as the latest hardship in Haiti and El Salvador and parts of Africa and Asia.
The tree is called the huarango. It lives [...]

BUENOS AIRES—At its broad mouth on the edge of Buenos Aires, the Riachuelo River looks more like a lake than a river. The water seems to be barely moving. It is dirty and smelly. And it may be more like a sludge pit than a lake, a sludge pit festooned with floating islands of plastic [...]